The MPLS-TE (Multi-Protocol Label Switching-Traffic Engineer) combines the advantages of multi-protocol label switching technology and traffic engineering technology, achieves dynamic adjustment and optimal allocation of network bandwidth resources in the packet switching and the 2-Layer switching, thus solves the network congestion problem. The GMPLS (Generalized Multi-Protocol Label Switching) is a further extension of MPLS-TE, which can not only support the IP (Internet Protocol) packet switching, but also support slot switching, wavelength switching and space switching (such as optical fiber switching and interface switching). Both the MPLS-TE and the GMPLS flood link resources through the routing protocol, before establishing a service, a display route is calculated, and the service is established through the signaling protocol. Both the MPLS-TE and the GMPLS proposed to use the unnumbered method to represent the link resources, and an unnumbered link refers to a link whose link interface does not have an IP address, and is represented with an Unnumbered Interface ID in a local network element.
The RSVP-TE (Resource Reservation Protocol-Traffic Engineer) is the existing signaling protocol which is most widely used, in the RFC3477, a method of using unnumbered link resources in the RSVP-TE signaling is proposed. As shown in FIG. 1, the expression way of the unnumbered link in an explicit route object (referred to as ERO) extends an unnumbered interface sub-object, and the expression way in other objects is similar thereto, which uses a two-tuple of router ID and interface to represent the unnumbered link resources. Because the unnumbered link resources in the signaling do not have the area ID information, it must require that the router ID is unique in all areas. In the corresponding routing protocolOpen Shortest Path First-Traffic Engineer (OSPF-TE), the flooding resources are represented with the routing area information, therefore, from the aspect of routing protocol, the router ID is limited within the area, and only needs to be unique in the area, for different areas, their router IDs may be the same value.
In the RFC3209, an Autonomous system number (abbreviated to as AS) sub-object is defined in the ERO to indicate that the next routing hop is a certain area, because it is a sub-object separated from the unnumbered interface sub-object, it has no restriction capability on the content of the unnumbered interface sub-object, and cannot be combined with the unnumbered interface sub-object, thus making the router ID unique only in the area. In addition, the object is not defined in the record route object (referred to as RRO), and an AS number defined by it only has two bytes, while an area ID defined in the OSPF-TE generally has four bytes, therefore the AS sub-object also needs to extend the field length.
The unnumbered interface in the RSVP-TE signaling protocol does not have the area ID, another problem brought about is that the RSVP-TE protocol processing module cannot determine the boundary nodes of the local area when the first node in each area establishes an intra-area service, and must inform the routing processing module of all subsequent routing information, and the routing processing module determines the boundaries of the local area, which increases the message processing overhead and reduces the service establishment speed.